Also of use might be the Osprey title 'U-Boat Crews 1914-45' which has some good U-Boat information despite being more about the crews than the boats.

There are some reasonably well represented 3D models of German WW1 U-Boats in the simulator '1914 Die Schalen des Zorns'. English title - The Shells of Fury, published by UBISOFT subsidiary Rondomedia:

There are some reasonably well represented 3D models of German WW1 U-Boats in the simulator '1914 Die Schalen des Zorns'. English title - The Shells of Fury, published by UBISOFT subsidiary Rondomedia:

Thanks for the interest in the project.
Sorry for the long time to reply I have been very busy.
At first, I want build one of the models U-19 or U-35, to Radio control, the U-35 may be a best model, because the rudder situation, located behind the propellers,however, the U-19 rudder is ahead of the propellers, so the u-35 is more maneoubrable that U-19. But U-19 is something diferent in the stern hull shape, and it is possible manoeuvring with the propellers in opposite turning.

So, I have not decide wath U boat build, it is depend on the best plans available.